203
FXUS64 KMRX 151949
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
349 PM EDT Sat Jun 15 2024

...New SHORT TERM, LONG TERM...


.SHORT TERM...
(This evening through Sunday)
Issued at 346 PM EDT Sat Jun 15 2024

Key Messages:

1. Nice this evening after it cools off after sunset.

2. Hot weather to continue on Sunday with a little more humidity.

3. Chances of showers and storms Sunday afternoon.

Discussion:

For tonight it should be quiet and relatively comfortable for being
in the midst of a heat wave.  For Sunday a return flow from the Gulf
will allow humidities to rise again, although looking upstream the
dewpoints aren`t overly rich back into central AL/MS where the air
is supposed to be coming from.  So, we have shaved back the
initialized dewpoints by around 2 degrees for Sunday, but that still
allows dewpoints to be around 70 degrees up the valley to at least
Knoxville.  Temperatures should rise into the 90s up through most of
the valley as well.

With higher moisture comes an increase in the chances for showers
and storms for Sunday, but with much higher PoPs near the mountains.
Also on Sunday the mid-level flow should be just about parallel to
the mountains, so keeping the higher PoPs there as well. Expecting
MLCAPES of about 1000-1500 J/kg, so gusty outflow winds, but mostly
sub-severe.

&&

.LONG TERM...
(Sunday night through next Saturday)
Issued at 346 PM EDT Sat Jun 15 2024

Key Messages:

1. Isolated to scattered storms are expected Monday, especially
along the higher terrain.

2. Hot weather to continue, pattern to turn dry Tuesday through the
remainder of the week.

Discussion:

The dominant player from Monday onwards will be the position and
strength of the upper level ridge. At the start of the long term
period the center of the ridge axis will be east of us. With time it
is scheduled to migrate northwards and bring a heat wave to the
northeastern US before relaxing southwards late in the week again.
Regardless of exact positioning, we will be running a few degrees
above normal every single afternoon in the long term period.

Beyond the temperatures, the only day with even slightly notable
rain chances is Monday. A weak disturbance in the upper flow will be
moving from south to north to our west along the Mississippi River.
While most convection should remain out west where better moisture
and dynamics will be present, the presence of weak upper flow may
allow for a few scattered showers and thunderstorms to make an
attempt against the influence of the upper ridge. General
thunderstorm hazards would be expected with these storms. After
Monday a lack of other synoptic players results in low to zero rain
chances for the remainder of the period, with any resulting
development likely to be isolated in nature. Finally, the GFS and
Euro both depict an interesting subtropical disturbance late in the
week approaching the SE US coastline, though low support from the
ensembles will keep it as a curious model feature for now.

&&

.AVIATION...
(18Z TAFS)
Issued at 145 PM EDT Sat Jun 15 2024

Dry day today with a light surface wind flow. Just scattered
cumulus clouds at TAF sites. Skies should be clearing tonight,
then scattered cumulus building again late Sunday morning; holding
off any mention of afternoon convection--better chances after 18z
on Sunday anyway. Did not put any fog to repeat at KTRI.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             73  95  74  94 /   0  30  20  20
Knoxville McGhee Tyson Airport, TN  68  92  72  92 /   0  20  20  30
Oak Ridge, TN                       68  93  71  92 /   0  20  20  30
Tri Cities Airport, TN              66  89  69  89 /   0  20  20  40

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

SHORT TERM...GM
LONG TERM....Wellington
AVIATION...